JP2008216454A - Developing device and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a developing device capable of sufficiently supplying a developer to a developer carrier in its lengthwise direction, and to provide an image forming apparatus. <P>SOLUTION: Toner in a toner cartridge 31 is received into a process frame 22 at a frame-side supply port 60, then conveyed to a frame-side return port 61 by an auger 35, and returned into the toner cartridge 31. The auger 35 rotates around an auger shaft 39 extending along the lengthwise (widthwise) direction of a developing roller 37, thereby supplying the toner to the developing roller 37 in its lengthwise direction. In a perpendicular direction, the lower end of the frame-side return port 61 is located above the center of the auger shaft 39. Accordingly, toner conveyed to the frame-side return port 61 by the auger 35 is made less likely to fall into the frame-side return port 61 and continuously conveyed by the auger 35. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an image forming apparatus such as a laser printer, and a developing device that is detachably attached to the image forming apparatus.

2. Description of the Related Art In an image forming apparatus such as a laser printer, a developing device that circulates a developer between a toner cartridge that stores the developer and a frame on which the toner cartridge is detachably mounted is known.
For example, in the developing device described in Patent Document 1, the frame and the toner cartridge of the developing device have a toner supply port that allows the inside of the frame and the inside of the toner cartridge to communicate with each other at a position substantially corresponding to the center of the toner cartridge. A pair of toner suction ports are formed on both sides of the toner supply port.

The developing device also includes a developing roller and an auger roller that rotates about an axis extending along the longitudinal direction of the developing roller.
In this developing device, the toner in the toner cartridge is supplied to the auger roller through the toner supply port, and is supplied to the developing roller side while being conveyed toward both sides in the axial direction (longitudinal direction of the developing roller) by the auger roller. Is done. The toner that has not been supplied to the developing roller is returned to the toner cartridge from each toner suction port, and is circulated between the toner cartridge and the frame.
JP 9-319202 A

  In the developing device of Patent Document 1, since each toner suction port is disposed between both ends of the auger roller in the axial direction, the toner supplied from the toner supply port to the auger roller is being conveyed to both ends of the auger roller in the axial direction. There is a risk of returning from each toner inlet to the toner cartridge. In this case, since the toner is not conveyed to both ends in the axial direction of the auger roller, there is a possibility that the toner is not sufficiently supplied to both ends in the longitudinal direction of the developing roller.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a developing device that can sufficiently supply a developer to the developer carrying member in the longitudinal direction, and an image forming apparatus to which the developing device is detachably mounted. There is to do.

  In order to achieve the above object, the invention described in claim 1 is a developing device, wherein the developer is supplied to a housing and a photosensitive member supported by the housing and forming an electrostatic latent image. A developer carrying member, a conveyance member that is supported by the housing and rotates about an axis extending along a longitudinal direction of the developer carrying member, and conveys the developer to be supplied to the developer carrying member; A toner cartridge that is detachable from the housing and contains a developer. The toner cartridge includes a first cartridge-side opening for supplying the developer to the housing; A cartridge-side second opening for receiving a developer is formed, and the housing is opposed to the cartridge-side first opening and for receiving the developer supplied from the cartridge-side first opening. Case side first opening and front Opposite to the cartridge side second opening, a housing side second opening for supplying developer to the cartridge side second opening is formed, and each opening is formed to extend in a substantially vertical direction. The transport member transports the developer from the housing-side first opening to the housing-side second opening, and the lower end of the housing-side second opening is above the axial center of the transport member in the vertical direction. It is characterized by being located.

  According to a second aspect of the present invention, in the first aspect of the present invention, the toner cartridge is supported in the toner cartridge, is provided on the shaft, is provided on the shaft, and rotates around the shaft to thereby move the toner cartridge. And a stirring member for stirring the developer, wherein the lower end of the cartridge-side first opening is positioned below the shaft center of the stirring member in the vertical direction. Yes.

The invention according to claim 3 is the invention according to claim 1 or 2, wherein the lower end of the housing side second opening is positioned above the lower end of the housing side first opening in the vertical direction. It is characterized by having.
The invention according to claim 4 is the invention according to any one of claims 1 to 3, wherein the housing side first opening and the housing side second opening are arranged side by side in the longitudinal direction. It is characterized by being.

According to a fifth aspect of the present invention, in the invention according to any one of the first to fourth aspects, the housing-side second opening is disposed at both ends of the conveying member in the longitudinal direction. It is a feature.
The invention according to claim 6 is the invention according to any one of claims 1 to 5, wherein the housing side first opening is larger than the cartridge side first opening.

The invention according to claim 7 is the invention according to any one of claims 1 to 6, wherein the cartridge side second opening is larger than the housing side second opening.
According to an eighth aspect of the present invention, there is provided an image forming apparatus comprising: the developing device according to any one of the first to seventh aspects; and an image forming apparatus main body to which the developing device is detachably mounted. It is characterized by having.

  According to the first and eighth aspects of the invention, in the developing device, the developer stored in the toner cartridge is received in the housing via the cartridge-side first opening and the housing-side first opening facing each other. Then, after being transported to the housing side second opening by the transporting member, it is received in the toner cartridge through the cartridge side second opening facing the housing side second opening. That is, in this developing device, the developer is circulated between the toner cartridge and the housing. The substantially vertical direction in which each opening extends is, for example, 45 to 135 ° with respect to the horizontal direction in order to ensure the circulation of the developer between the toner cartridge and the housing, preferably The direction is 80 to 100 °.

The conveying member conveys the developer by rotating about an axis extending along the longitudinal direction of the developer carrying member, and the developer is conveyed with respect to the developer carrying member in the longitudinal direction. Supply.
In the vertical direction, the lower end of the housing-side second opening is located above the axis center of the transporting member, so that the developer transported to the housing-side second opening by the transporting member is the housing-side second opening. It becomes difficult to fall into the opening and is subsequently transported by the transport member. Thereby, the developer can be sufficiently supplied to the developer carrying member in the longitudinal direction.

According to the second aspect of the present invention, in the vertical direction, the lower end of the cartridge side first opening is located below the axial center of the stirring member. Therefore, the developer stirred by the stirring member in the toner cartridge easily falls to the cartridge side first opening, and the developer can be reliably supplied to the casing through the cartridge side first opening. it can.
According to the invention described in claim 3, in the vertical direction, the lower end of the housing-side second opening is located above the lower end of the housing-side first opening. Therefore, the developer supplied from the cartridge-side first opening is easily received in the housing-side first opening.

On the other hand, in the case side second opening, the developer conveyed from the case side first opening by the conveying member is unlikely to fall, so this developer is continuously conveyed by the conveying member. Thus, the developer can be sufficiently supplied to the developer carrying member in the longitudinal direction.
According to the fourth aspect of the present invention, since the housing-side first opening and the housing-side second opening are arranged side by side in the longitudinal direction of the developer carrier, the longitudinal direction of the developer carrier is along. The transport member that rotates about the extending shaft can smoothly transport the developer from the housing side first opening to the housing side second opening.

According to the fifth aspect of the present invention, the housing-side second opening is disposed at both ends of the transport member in the longitudinal direction of the developer carrier. Therefore, since the developer reaches the housing-side second opening after being transported to both ends of the transport member, the developer can be sufficiently supplied over the longitudinal direction to the developer carrier. .
According to the sixth aspect of the present invention, the housing-side first opening is larger than the opposed cartridge-side first opening. Therefore, in the housing-side first opening, the toner cartridge supplied through the cartridge-side first opening. Can reliably accept the developer.

  According to the seventh aspect of the present invention, since the cartridge-side second opening is larger than the opposing housing-side second opening, the cartridge-side second opening provides the housing supplied via the housing-side second opening. The developer from can be reliably received.

1. 1 is a side sectional view showing an embodiment of a laser printer as an example of an image forming apparatus of the present invention. FIG. 2 is a side sectional view of the process cartridge (toner cartridge mounted state) of the laser printer shown in FIG.
As shown in FIG. 1, the laser printer 1 forms an image on a fed sheet 3 and a sheet feeding unit 4 for feeding the sheet 3 into a main body casing 2 as an example of an image forming apparatus main body. An image forming unit 5 for discharging the image, and a paper discharge unit 6 for discharging the paper 3 on which the image is formed.
(1) Main Body Casing The main body casing 2 is formed in a box shape, and an opening is formed in a side wall on one side thereof, and a front cover 7 that opens and closes the opening is provided. By opening the front cover 7, a process cartridge 17 (described later) can be attached to and detached from the main casing 2.

In the following description, the side on which the front cover 7 is provided is the front side (front side), and the opposite side is the rear side (back side). Further, the front side in the paper thickness direction in FIG. 1 is the left side, and the back side in the paper thickness direction in FIG. 1 is the right side. Moreover, the left-right direction and the width direction are synonymous. In the description of the process cartridge 17 and the toner cartridge 31 to be described later, a state in which a frame-side passage port 34 and a cartridge-side passage port 47 to be described later are oriented in the horizontal direction is used as a reference.
(2) Paper Feed Unit The paper feed unit 4 includes a paper feed tray 9, a paper feed roller 10, a paper feed pad 11, paper dust removing rollers 12 and 13, a registration roller 14, and a paper pressing plate 15. I have. The uppermost sheet 3 of the sheet pressing plate 15 is fed out one by one by the sheet feeding roller 10 and the sheet feeding pad 11 and passes through various rollers 12 to 14, and is then transferred to the image forming unit 5. (To be described later).
(3) Image Forming Unit The image forming unit 5 includes a scanner unit 16, a process cartridge 17 as an example of a developing device, and a fixing unit 18.
(3-1) Scanner Unit The scanner unit 16 is provided in the upper part in the main body casing 2, and includes a laser light emitting unit (not shown), a polygon mirror 19 that is rotationally driven, a plurality of lenses 20, and a plurality of reflecting mirrors 21. I have. The laser beam based on the image data emitted from the laser light emitting unit is reflected by the polygon mirror 19 as shown by a chain line, and passes or reflects through the plurality of lenses 20 and the plurality of reflecting mirrors 21, thereby exposing the process cartridge 17. A surface of a drum 25 (described later) is scanned.
(3-2) Process Cartridge The process cartridge 17 is disposed below the scanner unit 16 in the main body casing 2 and is detachably attached to the main body casing 2.

As shown in FIG. 2, the process cartridge 17 can be attached to and detached from a process frame 22 as an example of a housing in which a transfer path 29 that allows passage of the paper 3 is formed and a cartridge housing portion 33 of the process frame 22. And a toner cartridge 31 to be mounted.
In the process frame 22, a partition wall 57 extending in the vertical direction is provided at a substantially central position in the front-rear direction, the rear portion of the partition wall 57 is the developing unit 32, and the front portion of the partition wall 57 is The cartridge accommodating portion 33 described above is used. The partition wall 57 has a frame-side passage opening 34 formed therein.

In the developing unit 32, a photosensitive drum 25 as an example of a photosensitive member, a scorotron charger 26, a transfer roller 28, an auger 35 as an example of a conveying member, a supply roller 36, and a developing roller as an example of a developer carrier. 37 and a layer thickness regulating blade 38 are provided.
The photosensitive drum 25 is rotatably supported by the process frame 22. The scorotron charger 26 is supported by the process frame 22 above the photosensitive drum 25 and spaced from the photosensitive drum 25. The transfer roller 28 is disposed to face the photosensitive drum 25 from the lower side of the photosensitive drum 25, and is rotatably supported by the process frame 22. The developing roller 37 is long in the width direction and is disposed opposite to the front side of the photosensitive drum 25. The supply roller 36 is disposed opposite to the front side of the developing roller 37. The developing roller 37 and the supply roller 36 are rotatably supported by the process frame 22. The layer thickness regulating blade 38 includes a leaf spring member 45 formed in a thin plate shape, and a pressure contact rubber 46 provided at a lower end portion of the leaf spring member 45. The upper end portion of the leaf spring member 45 is fixed to the process frame 22, and the pressure contact rubber 46 presses the surface of the developing roller 37 by the elastic force of the leaf spring member 45. The auger 35 is disposed opposite to the frame side passage port 34 on the rear side of the frame side passage port 34. The auger 35 includes an auger shaft 39 as an example of an axis of the auger 35 and a screw 40 provided around the auger shaft 39. The auger shaft 39 is arranged so that the center of the auger shaft extends along the width direction, and is rotatably supported by the process frame 22 above the supply roller 36.

The toner cartridge 31 is detachably attached to the process frame 22 in the cartridge housing portion 33. The toner cartridge 31 is formed in a substantially cylindrical shape. The toner cartridge 31 is formed with a cartridge side passage port 47 (described later) for communicating the inside and the outside.
In the toner cartridge 31, an agitator 93 (described later) as an example of a stirring member is provided. The toner cartridge 31 contains a non-magnetic one-component positively chargeable toner as an example of a developer.

  The toner in the toner cartridge 31 is agitated by the rotation of the agitator 93, received from the cartridge side passage port 47 into the frame side passage port 34, and discharged into the developing unit 32. The discharged toner is supplied to the supply roller 36 while being conveyed from the center in the width direction to both sides in the width direction by the rotation of the auger 35. Part of the toner is returned to the toner cartridge 31 through the frame side passage port 34 and the cartridge side passage port 47. This ensures toner circulation between the toner cartridge 31 and the developing unit 32 of the process frame 22.

  The toner supplied to the supply roller 36 is supplied to the developing roller 37 by the rotation of the supply roller 36. At this time, the toner is frictionally charged positively between the supply roller 36 and the developing roller 37. Subsequently, the toner supplied to the developing roller 37 enters between the pressure contact rubber 46 and the developing roller 37 as the developing roller 37 rotates, and the layer thickness is regulated between them. It is carried on the surface of 37 as a thin layer.

The surface of the photosensitive drum 25 is first uniformly charged positively by the scorotron charger 26 as the photosensitive drum 25 rotates, and then exposed by the laser beam from the scanner unit 16 to obtain image data. An electrostatic latent image based on is formed. Next, the toner carried on the surface of the developing roller 37 is supplied to the electrostatic latent image formed on the surface of the photosensitive drum 25 when the toner carried on the surface of the developing roller 37 contacts the photosensitive drum 25 by rotation of the developing roller 37. Is done. As a result, the electrostatic latent image is developed (visualized), and a toner image is carried on the surface of the photosensitive drum 25. This toner image is transferred onto the sheet 3 conveyed between the photosensitive drum 25 and the transfer roller 28 (transfer position) in the transfer path 29.
(3-3) Fixing Unit The fixing unit 18 is provided on the rear side of the process cartridge 17 as shown in FIG. The fixing unit 18 includes a heating roller 48, a pressure roller 49 that is pressed against the heating roller 48 from below, and a pair of conveying rollers 50 disposed on the rear side thereof.

In the fixing unit 18, the toner transferred to the sheet 3 at the transfer position is thermally fixed while the sheet 3 passes between the heating roller 48 and the pressure roller 49, and then the sheet 3 is transported as a pair. The paper is conveyed to the paper discharge unit 6 by the roller 50.
(4) Paper Discharge Unit The paper discharge unit 6 includes a paper discharge path 51, a paper discharge roller 52, and a paper discharge tray 53. The sheet 3 conveyed from the fixing unit 18 to the sheet discharge path 51 is conveyed from the sheet discharge path 51 to the sheet discharge roller 52 and is discharged onto the sheet discharge tray 53 by the sheet discharge roller 52.
2. Details of Process Cartridge FIG. 3 is a side sectional view of the process cartridge (toner cartridge detached state) of the laser printer shown in FIG. FIG. 4 is a partially cutaway perspective view of the process cartridge as viewed obliquely from the right front side. FIG. 5 is an exploded perspective view of the process cartridge as viewed obliquely from the right front side. FIG. 6 is a perspective view of the process cartridge (toner cartridge detached state) with the shutter omitted. FIG. 7 is a perspective view of the toner cartridge (in the state where the inner housing is in the open position) as viewed obliquely from the rear left side. FIG. 8 is a perspective view of the toner cartridge (in a state where the inner housing is in the closed position) as viewed obliquely from the left rear side. FIG. 9 is a perspective view of the inner housing of the toner cartridge shown in FIG. 8 as viewed obliquely from the rear left side. FIG. 10 is a plan sectional view of the main part of the process cartridge. FIG. 11 is an AA arrow view of FIG.
(1) Process Frame As shown in FIGS. 3 and 5, the process frame 22 integrally includes the developing unit 32 and the cartridge storage unit 33 as described above.
(1-1) Developing Unit The developing unit 32 is integrally provided with an upper wall 54, a bottom wall 55, both side walls 56, and a partition wall 57. Both side walls 56 are arranged to face each other with a space therebetween in the width direction. Each side wall 56 is disposed along the front-rear direction.

The developing roller 37 is supported by the process frame 22 by being rotatably supported by the front side portions of the side walls 56.
The supply roller 36 is supported by the process frame 22 by being rotatably supported by the front side portions of the side walls 56 on the front side of the developing roller 37.
The auger 35 is supported on the process frame 22 by the auger shaft 39 being rotatably supported on the front side portions of the side walls 56 on the upper side of the supply roller 36.

Further, as shown in FIG. 3, a curved portion along the outer peripheral surface of the toner cartridge 31 is formed in the partition wall 57 in the middle of the vertical direction.
As shown in FIG. 6, the frame side passage port 34 is formed in the curved portion of the partition wall 57.
Specifically, three frame side passage openings 34 are formed at intervals in the width direction. Each frame side passage opening 34 is formed in a substantially rectangular shape elongated in the width direction. Of the frame side passage ports 34, the frame side passage port 34 formed at the center in the width direction of the partition wall 57 is a frame side supply port 60 as an example of the housing side first opening. The frame-side passage openings 34 on both sides in the width direction are frame-side return openings 61 as an example of the housing-side second opening.

As shown in FIG. 11, the frame side supply port 60 and the frame side return port 61 are arranged side by side in the width direction. Further, in the vertical direction, the lower end of the frame-side return port 61 is above the lower end of the frame-side supply port 60 and above the axis center of the auger 35 (center line indicated by a one-dot chain line in the auger shaft 39). Located (see also enlarged view).
The width direction outer end of the frame side return port 61 corresponds to the width direction inner side (width direction center side) of the roller portion of the supply roller 36 and the width direction both ends of the auger 35. Placed in position.

Further, as shown in FIG. 6, a frame side seal 62 for preventing toner leakage from the frame side passage port 34 is provided at the peripheral portion of the frame side passage port 34 at the curved portion of the partition wall 57. ing.
The frame-side seal 62 is formed in a band shape extending in the width direction from an elastic material such as felt, and a notch portion is formed corresponding to each frame-side passage port 34. The frame side seal 62 is stuck along the width direction in the middle of the partition wall 57 in the vertical direction so that each notch portion faces each frame side passage port 34.

Accordingly, the frame side seal 62 covers the peripheral edge of each frame side passage port 34 and is continuous with the surface (front surface) of the curved portion of the partition wall 57 so as to be continuous between the frame side passage ports 34. Provided.
(1-2) Cartridge Storage Unit The cartridge storage unit 33 includes both side plates 63 and a bottom plate 64 as shown in FIG. The both side plates 63 and the bottom plate 64 of the cartridge housing portion 33 are formed integrally with the both side walls 56 and the bottom wall 55 of the developing portion 32 continuously.

A shutter support portion 65 is provided on the inner surface in the width direction of both side plates 63. The shutter support portion 65 has a substantially rectangular shape that bulges inward from the inner surface in the width direction of both side plates 63, and is provided at the rear end portion of the both side plates 63 so as to extend in the vertical direction.
A shutter guide portion 144 is provided on the inner surface in the width direction of each shutter support portion 65. Each shutter guide portion 144 has a protruding ridge that bulges inward from the inner surface in the width direction of the shutter support portion 65, and is disposed to face the curved portion of the partition wall 57 with a slight space in the front-rear direction. Each shutter guide portion 144 is formed in a curved shape having substantially the same curvature as the curved portion of the partition wall 57.

The upper end surface of each shutter support portion 65 is disposed slightly below the upper end edge of each side plate 63. The upper end surface of each shutter support portion 65 is an upper fixing portion 66.
The bottom plate 64 is formed with a lower fixing portion 67 that slightly protrudes to the front side at the center in the width direction of the front end edge.
The cartridge housing portion 33 is provided with a shutter 68 that opens and closes the frame-side passage port 34.

The shutter 68 has a substantially rectangular plate shape extending in the width direction, and is formed in a curved shape having substantially the same curvature as the curved portion of the partition wall 57. The shutter 68 is formed so as to extend between the shutter guide portions 144 in the width direction and slightly shorter than the shutter guide portions 144 in the vertical direction. Further, the shutter 68 is formed with three shutter openings 69 corresponding to the respective frame side passage openings 34 and capable of facing them.
The shutter 68 is disposed to face the curved portion of the partition wall 57, and both end portions in the width direction are slidably sandwiched between the partition wall 57 and each shutter guide portion 144 (see FIG. 3).

  As a result, the shutter 68, along each shutter guide portion 144, has an open position (see FIG. 2) for opening the frame side passage port 34 and a closed position (see FIGS. 3 and 5) for closing the frame side passage port 34. ) To be swingable in the vertical direction. When the shutter 68 is in the open position, each frame-side passage port 34 faces the corresponding shutter opening 69 and is opened outward (front side). When the shutter 68 is in the closed position, each frame-side passage port 34 is closed from the front side by a portion below the shutter opening 69 in the shutter 68.

The cartridge housing portion 33 is provided with a swing arm 70. The swing arm 70 is formed in a substantially U shape in plan view. The swing arm 70 is integrally provided with a gripping rod 71 extending in the width direction and arm side plates 72 extending rearward from both widthwise ends of the gripping rod 71.
A boss 73 protruding outward in the width direction is provided at the rear end of each arm side plate 72. Each boss 73 is rotatably supported in a round hole 74 formed in each side plate 63.

A receiving recess 75 is formed at the upper edge of the rear end of each arm side plate 72 so as to be cut out so as to be recessed downward.
A grip portion 76 that is recessed upward is formed at the center in the width direction of the grip rod 71. In addition, pressing protrusions 77 are provided at both ends in the width direction of the gripper 71.
The swing arm 70 has a boss 73 of each arm side plate 72 as a fulcrum, a pressing release position where the lower end edge of each arm side plate 72 contacts the front end edge of the bottom plate 64 (see FIGS. 3 and 5), and the toner cartridge 31 It swings between a pressing position (see FIGS. 2 and 4) for pressing the toner cartridge 31 from the front side when it is accommodated in the cartridge accommodating portion 33.
(2) Toner Cartridge As shown in FIGS. 7 to 9, the toner cartridge 31 includes an inner casing 81 that stores toner and an outer casing 82 that stores the inner casing 81.
(2-1) Inner Housing As shown in FIG. 9, the inner housing 81 includes a cylindrical inner peripheral wall 83 extending in the width direction, and a disk-shaped inner side wall that closes both ends of the inner peripheral wall 83 in the width direction. 84 is integrally provided.

Each inner side wall 84 is provided with a thick disc-shaped boss portion 85 bulging outward in the width direction at the center.
Further, each inner side wall 84 is provided with a slide projection 86 on the upper side thereof, on the radially outer side from the boss portion 85. The slide protrusion 86 is formed in a side-view arc shape (arc shape with a central angle of about 60 °) along the outer peripheral surface of the inner side wall 84, and is provided so as to protrude outward in the width direction from the inner side wall 84.

Each inner side wall 84 is provided with a pair of sandwiching protrusions 87 protruding radially from the peripheral end surface at the rear side portion. The pair of sandwiching protrusions 87 are arranged on the circumferential end surface of each inner side wall 84 with a circumferential interval (interval corresponding to the circumferential length of the shutter 68).
In the inner peripheral wall 83, an inner passage port 89 that forms the cartridge side passage port 47 is formed in the surrounding portion 88 surrounded by a pair of sandwiching protrusions 87 (four sandwiching protrusions 87) disposed on both sides in the width direction. .

  The inner passage port 89 is formed in the upper portion of the surrounding portion 88. Specifically, three inner passage openings 89 are formed at intervals in the width direction. Each inner passage port 89 is formed in a substantially rectangular shape elongated in the width direction. Among the inner passage openings 89, the inner passage opening 89 formed at the center in the width direction is an inner supply opening 90 as an example of the cartridge-side first opening, and the inner passage openings 89 on both sides in the width direction of the inner supply opening 90. Is an inner return port 91 as an example of the cartridge side second opening.

  As shown in FIG. 2, the above-described agitator 93 is provided in the inner housing 81. The agitator 93 includes an agitator shaft 94 that extends in the width direction as an example of an axis of the agitator 93, and a stirring blade 95 as an example of a stirring unit that extends radially outward from the agitator shaft 94. The agitator shaft 94 is rotatably supported by both inner side walls 84 and is rotated by a driving force from a motor (not shown) during image formation. As a result, the stirring blade 95 also rotates, and the toner in the toner cartridge 31 is stirred as described above.

Here, in a state where the inner housing 81 is in an open position (described later), the lower end of the inner supply port 90 is positioned below the axial center of the agitator 93 (the center of the agitator shaft 94) in the vertical direction. Yes.
(2-2) Outer casing The outer casing 82 is formed to be slightly larger in the width direction and the radial direction than the inner casing 81 in order to accommodate the inner casing 81 in a rotatable manner. As shown in FIG. 8, the outer casing 82 integrally includes a substantially cylindrical outer peripheral wall 101 extending in the width direction and a disk-shaped outer side wall 102 that closes both ends of the outer peripheral wall 101 in the width direction. ing.

  Each outer side wall 102 is formed with a circular boss hole 103 for receiving the boss portion 85. In addition, each outer side wall 102 is formed with a slide hole 104 through which the slide protrusion 86 is inserted in the upper portion thereof. The slide hole 104 is disposed so as to face the slide protrusion 86 in the width direction. The slide hole 104 is formed in a circular arc shape in a side view having a longer circumference than the slide protrusion 86.

Further, an upper fixed portion 105 protruding rearward is formed on the rear side of the peripheral end surface of each outer side wall 102. A positioning boss 106 protruding outward in the width direction is provided at the rear end portion of the upper fixed portion 105.
Further, as shown in FIG. 5, a pressed portion 107 that bulges to the front side is provided below the front end of the peripheral end surface of each outer side wall 102. The pressed portion 107 has a substantially rectangular shape in front view, and is formed in a substantially arc shape in side view from the front side to the lower side of each outer side wall 102.

  As shown in FIG. 8, the outer peripheral wall 101 is formed with four long holes 108 through which a pair of sandwiching protrusions 87 (four sandwiching protrusions 87) are inserted at both ends in the width direction. Each long hole 108 is disposed so as to face each clamping protrusion 87 in the radial direction. Each long hole 108 has a substantially rectangular shape extending in the vertical direction when viewed from the back, and is formed with a length corresponding to the swing range between the open position and the closed position of the shutter 68 described above.

The outer peripheral wall 101 has an outer passage port 109 that forms a cartridge side passage port 47 between the four long holes 108 (between the upper two long holes 108 and the lower two long holes 108). Is formed.
Three outer passage ports 109 are formed at intervals in the width direction. Each outer passage port 109 is formed in a substantially rectangular shape elongated in the width direction. The size of each outer passage port 109 is substantially equal to the size of each inner passage port 89. Of the outer passage ports 109, the outer passage port 109 formed at the center in the width direction is an outer supply port 110 as an example of the cartridge-side first opening, and the outer passage ports 109 on both sides in the width direction of the outer supply port 110. Is an outer return port 111 as an example of the cartridge side second opening.

  As shown in FIG. 11, in a state where the toner cartridge 31 is mounted on the process frame 22, the outer supply port 110 faces the frame side supply port 60, and the two outer return ports 111 have two frame side return ports 61. opposite. Here, the outer supply port 110 is formed smaller than the frame side supply port 60. Further, the outer return port 111 is formed larger than the frame side return port 61.

Further, as shown in FIG. 5, a grip portion 113 is provided on the front side of the outer peripheral wall 101 at the center in the width direction.
The grip portion 113 includes a substantially rectangular upper gripping plate 114 protruding forward from the outer peripheral wall 101 and a locking arm 115 having a substantially J-shape in side view extending downward from the upper gripping plate 114. The upper end of the locking arm 115 is swingably supported by a support shaft 116 provided on the upper grip plate 114. A locking claw 117 that locks to the lower fixing portion 67 is provided at the lower end of the locking arm 115. In the vicinity of the upper end portion of the locking arm 115, a substantially rectangular lower gripping plate 118 that protrudes forward is provided. The lower gripping plate 118 is disposed so as to extend in parallel with the upper gripping plate 114 at a distance.

A compression spring (not shown) that urges the upper gripping plate 114 and the lower gripping plate 118 in a direction to separate them is interposed.
(2-3) Relative Arrangement of Inner Housing and Outer Housing As shown in FIG. 2, the inner housing 81 is rotatably accommodated in the outer housing 82.
Specifically, the outer peripheral surface of the inner peripheral wall 83 is fitted into the inner peripheral surface of the outer peripheral wall 101 so as to be slidable in the circumferential direction. Although not shown, the outer peripheral surfaces of both inner side walls 84 are fitted to the inner peripheral surfaces of both outer side walls 102 so as to be slidable in the circumferential direction. As shown in FIGS. 7 and 8, a boss portion 85 is rotatably supported in the boss hole 103. A slide protrusion 86 is inserted into the slide hole 104. Each clamping protrusion 87 is inserted into each long hole 108, and each clamping protrusion 87 protrudes radially outward from each long hole 108.

The inner housing 81 has a closed position (see FIG. 8) where the inner passage port 89 does not face the outer passage port 109 and an open position (see FIG. 8) where the inner passage port 89 faces the outer passage port 109. Relative rotation about the boss portion 85 is allowed.
When the inner housing 81 is disposed at the closed position, as shown in FIG. 8, the slide protrusions 86 are disposed at the front end portions of the slide holes 104, and the holding protrusions 87 are disposed at the upper end portions of the long holes 108. The inner passage 89 is disposed above the outer passage 109, and the outer passage 109 is closed by the lower portion of the surrounding portion 88.

Then, with the boss portion 85 as a fulcrum, the inner casing 81 is rotated relative to the outer casing 82 in a direction (lower side) in which the inner passage port 89 faces the outer passage port 109. Then, each slide projection 86 slides each slide hole 104 from the front end portion toward the rear end portion, and each clamping projection 87 slides each long hole 108 from the upper end portion toward the lower end portion.
After that, when each slide protrusion 86 comes into contact with the rear end edge of each slide hole 104 and each holding protrusion 87 comes into contact with the lower end edge of each long hole 108, as shown in FIG. Placed in.

When the inner casing 81 is disposed at the open position, each slide projection 86 is disposed at the rear end portion of each slide hole 104, and each clamping projection 87 is disposed at the lower end portion of each elongated hole 108. 89 opposes the outer passage port 109, and these are communicated and opened.
When the inner casing 81 is rotated relative to the outer casing 82 in the direction in which the inner passage port 89 rises from the outer passage port 109 with the boss portion 85 as a fulcrum, the slide protrusions 86 are moved to the respective slides 86. As shown in FIG. 8, the inner casing 81 is disposed in the closed position as abutting against the front end edge of the hole 104 and the holding protrusions 87 abutting against the upper end edges of the long holes 108.
(3) Attaching / detaching the toner cartridge to / from the process frame (3-1) Attaching the toner cartridge to the process frame To attach the toner cartridge 31 to the process frame 22, as shown in FIG. The plate 114 and the lower grip plate 118 are sandwiched in the direction in which they approach each other. The toner cartridge 31 (the inner casing 81 is disposed at the closed position) is replaced with the cartridge housing portion 33 (the shutter 68 is disposed at the closed position, and the swing arm 70 is disposed at the press release position). ).

At this time, each positioning boss 106 is placed on each upper fixing portion 66, and a pair of clamping protrusions 87 (see FIGS. 7 and 8) on both sides in the width direction are at the upper ends of both ends in the width direction of the shutter 68. Each of the slide protrusions 86 is fitted in each of the receiving recesses 75 while sandwiching the edge and the lower edge.
Thereafter, when the holding of the grip portion 113 is released, as shown in FIG. 2, the locking claw 117 is locked to the lower fixing portion 67 and the toner cartridge 31 is stored in the cartridge storage portion 33.

The outer casing 82 has a positioning boss 106 mounted on the upper fixed portion 66 (see FIG. 5) and a locking claw 117 locked on the lower fixed portion 67. It is fixed to the accommodating part 33. Thereby, the mounting of the toner cartridge 31 to the process frame 22 is completed.
Then, the swing arm 70 is swung from the press release position to the press position. Then, as shown in FIGS. 2 and 4, each pressing projection 77 presses each pressed portion 107 toward the rear side. As a result, the toner cartridge 31 is pressed toward the developing unit 32.

  Further, when the swing arm 70 is swung from the press release position to the press position, each slide protrusion 86 fitted in each receiving recess 75 is moved to each slide hole 104 along with the swing of each arm side plate 72. Is slid rearward and is arranged at the rear end of each slide hole 104. Further, a pair of sandwiching protrusions 87 on both sides in the width direction slides through the long holes 108 while sandwiching the shutter 68 and is disposed at the lower end of each long hole 108 (see FIG. 7).

As a result, as shown in FIG. 2, the inner casing 81 is disposed in the open position, the inner passage port 89 faces the outer passage port 109, and these are communicated with each other. Further, the shutter 68 is disposed at the open position, and the frame side passage port 34 faces the cartridge side passage port 47 (the inner passage port 89 and the outer passage port 109), and these are communicated with each other.
Then, as shown by the bold arrows in FIG. 10, at the time of image formation, the toner in the inner casing 81 is supplied from the inner supply port 90 and the outer supply port 110 to the developing unit 32 side by the stirring of the agitator 93. At the side supply port 60, it is received in the developing unit 32.

On the other hand, the toner supplied into the developing unit 32 from the frame side supply port 60 is conveyed from the center in the width direction to both sides in the width direction by the auger 35 and is supplied to the supply roller 36 in the middle thereof. The toner supplied to the supply roller 36 is supplied to the developing roller 37 as described above. The toner that has not been supplied to the supply roller 36 is conveyed to the frame-side return port 61, passes through the outer return port 111 and the inner return port 91, and is returned from the developing unit 32 into the inner housing 81. As a result, the toner is circulated between the developing unit 32 and the inner casing 81. At this time, in order to ensure the toner circulation in the horizontal direction between the developing unit 32 and the inner housing 81, the frame side passage port 34 and the cartridge side passage port 47 are arranged in a substantially vertical direction (with respect to the horizontal direction, For example, it extends in the direction of 45 to 135 °, preferably 80 to 100 ° (see FIG. 2).
(3-2) Removal of Toner Cartridge from Process Frame To release the toner cartridge 31 from the process frame 22, first, the swing arm 70 is swung from the pressed position to the pressed release position (see FIGS. 3 and 5). ). Then, the pressing protrusions 77 are separated from the pressed parts 107 and the pressing of the toner cartridge 31 against the developing unit 32 is released.

  Further, when the swing arm 70 is swung from the press position to the press release position, the slide protrusions 86 fitted in the receiving recesses 75 are moved to the state shown in FIG. As shown, each slide hole 104 is slid forward and disposed at the front end of each slide hole 104. Further, a pair of clamping protrusions 87 on both sides in the width direction are arranged at the upper end of each slot 108 by sliding each slot 108 upward while holding the shutter 68.

As a result, the inner housing 81 is disposed at the closed position, the lower portion of the surrounding portion 88 faces the outer passage port 109, and the outer passage port 109 is closed. Further, the shutter 68 is disposed at the closed position, and the frame side passage opening 34 is closed to face the shutter 68.
Then, when the upper gripping plate 114 and the lower gripping plate 118 are gripped in the direction in which they are close to each other, the locking with respect to the lower fixing portion 67 of the locking claw 117 is released (see FIG. 2). If the toner cartridge 31 is pulled out from the cartridge housing portion 33 as it is, the toner cartridge 31 is detached from the process frame 22 (see FIG. 5).
3. Advantageous Effects of Embodiment In this process cartridge 17, as indicated by the bold arrow in FIG. 10, the toner contained in the toner cartridge 31 is processed through the inner supply port 90, the outer supply port 110 and the frame side supply port 60. The frame 22 (specifically, the developing unit 32) is received. The toner is conveyed to the frame side return port 61 by the auger 35 and then received in the toner cartridge 31 through the frame side return port 61, the outer return port 111, and the inner return port 91. That is, in the process cartridge 17, toner is circulated between the toner cartridge 31 and the process frame 22.

The auger 35 conveys the toner by rotating around an axis (auger shaft 39) extending along the longitudinal direction (width direction) of the developing roller 37, and the toner is transferred to the developing roller 37 with respect to the auger 35. Supply over the longitudinal direction (see FIG. 2).
As shown in FIG. 11, the lower end of the frame-side return port 61 is positioned above the center of the auger shaft 39 (see the dashed line in the drawing) in the vertical direction. The toner conveyed to the opening 61 is unlikely to fall to the frame side return opening 61 and is subsequently conveyed by the auger 35. Thereby, the toner can be sufficiently supplied to the developing roller 37 in the longitudinal direction.

  As shown in FIG. 2, in a state where the inner casing 81 is in the open position, the lower ends of the inner supply port 90 and the outer supply port 110 in the vertical direction are from the center of the axis of the agitator 93 (the agitator shaft 94). Is also located below. Therefore, the toner stirred by the agitator 93 in the toner cartridge 31 easily falls to the inner supply port 90 and the outer supply port 110, and this toner is supplied to the process frame via the inner supply port 90 and the outer supply port 110. 22 can be reliably supplied.

Further, as shown in FIG. 11, the lower end of the frame side return port 61 is located above the lower end of the frame side supply port 60 in the vertical direction. Therefore, the frame-side supply port 60 can easily accept the toner supplied from the inner supply port 90 and the outer supply port 110.
On the other hand, at the frame-side return port 61, the toner conveyed from the frame-side supply port 60 by the auger 35 is unlikely to fall, so this toner is continuously conveyed by the auger 35. Thereby, the toner can be sufficiently supplied to the developing roller 37 in the longitudinal direction.

Further, since the frame side supply port 60 and the frame side return port 61 are arranged side by side in the longitudinal direction (width direction) of the developing roller 37, the auger rotating around the auger shaft 39 extending along the width direction. No. 35 can smoothly convey the toner from the frame side supply port 60 to the frame side return port 61.
Further, the frame side return ports 61 are disposed at both ends of the auger 35 in the width direction. Therefore, since the toner reaches the frame side return port 61 after being conveyed to both ends in the width direction of the auger 35, the toner is sufficiently supplied to the developing roller 37 in the longitudinal direction (width direction). be able to.

Further, since the frame-side supply port 60 is larger than the opposed outer supply port 110, the frame-side supply port 60 can reliably receive the toner from the toner cartridge 31 supplied via the outer supply port 110. .
Further, since the outer return port 111 is larger than the opposing frame side return port 61, the outer return port 111 can reliably receive the toner from the process frame 22 supplied via the frame side return port 61. .
4). Modification (1) In the above-described embodiment, the process cartridge 17 is integrally provided with the photosensitive drum 25 and the developing roller 37, and the process cartridge 17 is detachably attached to the main body casing 2. In addition to this, for example, while the process cartridge 17 is a developing cartridge that does not include the photosensitive drum 25, another unit (drum cartridge) that includes the photosensitive drum 25 is provided, and the developing cartridge is attached to and detached from the drum cartridge. You may attach freely.

Further, the photosensitive drum 25, the scorotron charger 26 and the transfer roller 28 can be provided in the main casing 2, and the developing cartridge can be detachably attached to the main casing 2.
(2) In the above-described embodiment, the monochrome laser printer 1 is exemplified. However, for example, the image forming apparatus of the present invention may be configured as a color laser printer (including a tandem type and an intermediate transfer type). it can.

1 is a side sectional view showing an embodiment of a laser printer as an example of an image forming apparatus of the present invention. FIG. 2 is a side sectional view of a process cartridge (toner cartridge mounted state) of the laser printer shown in FIG. 1. FIG. 2 is a side sectional view of a process cartridge (toner cartridge detached state) of the laser printer shown in FIG. 1. FIG. 5 is a partially cutaway perspective view of the process cartridge as viewed obliquely from the right front side. FIG. 3 is an exploded perspective view of the process cartridge as viewed obliquely from the front right side. FIG. 6 is a perspective view of a process cartridge (toner cartridge detached state) with a shutter omitted. FIG. 4 is a perspective view of the toner cartridge (in a state where an inner housing is in an open position) as viewed obliquely from the left rear side. FIG. 4 is a perspective view of a toner cartridge (in a state where an inner housing is in a closed position) as viewed obliquely from the left rear side. FIG. 9 is a perspective view of the inner housing of the toner cartridge shown in FIG. 8 as viewed obliquely from the left rear side. FIG. 3 is a plan sectional view of a main part of a process cartridge. It is an AA arrow line view of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Laser printer 2 Main body casing 17 Process cartridge 22 Process frame 25 Photosensitive drum 31 Toner cartridge 35 Auger 37 Developing roller 39 Auger shaft 60 Frame side supply port 61 Frame side return port 90 Inner supply port 91 Inner return port 93 Agitator 94 Agitator shaft 95 Stirring blade 110 Outer supply port 111 Outer return port

Claims (8)

A housing,
A developer carrier that is supported by the housing and supplies a developer to a photoreceptor on which an electrostatic latent image is formed;
A transport member that is supported by the housing and rotates about an axis extending along a longitudinal direction of the developer carrier, and transports the developer to be supplied to the developer carrier;
A toner cartridge that is detachable from the housing and contains a developer;
The toner cartridge has a cartridge-side first opening for supplying developer to the housing and a cartridge-side second opening for receiving developer from the housing,
The housing faces the cartridge side first opening, faces the housing side first opening for receiving the developer supplied from the cartridge side first opening, and the cartridge side second opening, and develops the housing. A housing-side second opening for supplying the agent to the cartridge-side second opening is formed,
Each of the openings is formed to extend in a substantially vertical direction,
The transport member transports the developer from the housing side first opening to the housing side second opening,
In the vertical direction, the lower end of the housing-side second opening is located above the axial center of the conveying member. A stirring member that is supported in the toner cartridge and includes a shaft, and a stirring member that is provided on the shaft and that stirs the developer in the toner cartridge by rotating about the shaft;
2. The developing device according to claim 1, wherein a lower end of the first opening on the cartridge side is positioned below a shaft center of the stirring member in a vertical direction.   The developing device according to claim 1, wherein a lower end of the housing-side second opening is positioned above a lower end of the housing-side first opening in the vertical direction.   The developing device according to claim 1, wherein the housing-side first opening and the housing-side second opening are arranged side by side in the longitudinal direction.   5. The developing device according to claim 1, wherein the housing-side second opening is arranged at both ends of the transport member in the longitudinal direction. 6.   The developing device according to claim 1, wherein the housing-side first opening is larger than the cartridge-side first opening.   The developing device according to claim 1, wherein the cartridge side second opening is larger than the housing side second opening. A developing device according to any one of claims 1 to 7,
An image forming apparatus comprising: an image forming apparatus main body to which the developing device is detachably mounted.

Images